Numerous envelopes and insert materials for such envelopes have been created to accommodate a growing demand for expeditious mailings. Such mailings, normally used in conjunction with computer-generated imprinting equipment, have been used with increased frequency for billing, statements and notices and other like applications. Most of the known business form structures have been produced as continuous webs of detachable envelopes each of which is a self-contained assembly suitable for processing and mail handling. Normally, however, the series connected envelopes are not separated from each other until they have been fully processed to facilitate handling thereof, particularly through high speed printers and other printing or typing apparatus.
One of the problems in the manufacture of continuous envelopes with inserts is the problem of maintaining the insert material in a desired position. This is important because while the envelopes are processed, they normally go through high speed impact printers which address the envelopes and type other pertinent information on the single or multiple page inserts. In order to image the information in the appropriate spaces, the positions of the inserts must be predictable and, accordingly, are normally attached to the outer envelope to prevent relative movements therebetween. This, however, may frustrate simple removal of the insert from the envelope.
Previous products all utilize cold or water soluble glue to fasten the front and back sheets of the outer envelope and, in some instances, to glue the insert to the front and back sheets. The glue does not dry thoroughly for hours after the assembly has been folded into a flat pack suitable for computer printer feeding. The continuous web is folded at succeeding points where adjacent envelopes are detachably connected to each other. Folding before the glue has dried produces a condition known as "tenting" where the various plies of the assembly shift relative to each other to facilitate folding and take a set. When the glue dries after the assembly is folded into a flat pack, any attempts to unfold the web along the fold lines leaves residual protuberances running across the width of the web at each fold line. This "tenting" problem is not acceptable for proper feeding into a computer printer since it frequently causes the printer to jam up, this resulting in down time and increased mailing costs. All previous products exhibit this condition in various degrees, the problem becoming more aggravated the more plies that are joined to each other and, therefore, the more glue that is used. Many forms of tenting are so severe at the manufacturing stage that the product is never shipped to the consumer. Other flat packs that are shipped do not feed at all or feed so poorly that printers cannot be allowed to run unattended. In addition to the added expense in requiring supervision of the computer printers, all the forms that are damaged during jam-ups must, of course, be replaced and this still further increases the costs.
Known sealed envelope assemblies and the methods of making the same have also been wasteful in terms of the inefficiency of conversion of paper stock to completed mailing assemblies. Firstly, because cold glue is basically uncontrollable as to the width of the glue line produced, heavily applied glue has a tendency to bleed to a wider width when compressed between plies. Previous manufactures of pre-stuffed envelopes, therefore, allow for wide tolerances in gluing, this requiring larger envelopes in relation to the insert sizes to assure that there is no adhesion of the insert to the outer envelope. However, this adds to the waste factor and it is estimated that the total waste at the manufacturing level may be as high as 35-40 percent, a situation that can no longer be tolerated in this current day of shortages and dwindling supplies of natural resources.
Pre-inserted mailers normally require a large volume to be cost efficient. The large volume users rarely keep "hard copy" records of transactions printed on the mailers since the information is normally available in computer storage. When the envelopes are run through a high-speed impact printer, the printing head strikes the front of the envelope at different surface areas thereof to image information on selected portions of the insert sheets or plies by use of selectively coated carbon or other image transfer means between the sheets. However, since all the information with the exception of the mailing address that is recorded on the insert need not be reproduced on the face of the envelope, a "record copy" is normally placed on top of the envelope, the "record copy" usually having a carbon patch only behind the location where the name and address of the addressee is printed so that the balance of the information is not imaged on the top surface of the envelope. Since, as noted above, the record copy is usually discarded, this creates additional waste and requires an additional time-consuming operation on a business forms decollator for its removal.
In addition to being inefficient, the prior art procedures for the manufacture of two-way mailers require the use of a great number of sheets or plies in the formation of the mailer, including the cover sheet, the outgoing envelope, the return envelope and the back sheet of the outgoing envelope. Upon receipt, the recipient destroys the outgoing envelope, removes the document and uses the return envelope for inserting all or a portion of the document for return to the sender with, usually, a remittance. The discarding of the outer envelope by the recipient, together with the above-noted discarding of the cover sheet, therefore, represents a fifty percent waste of materials.
U.S. Pat. No. 3,350,988, for a method of making continuous form envelopes, teaches the use of thermo-sensitive plastic as the outside plies or sheets. Plastic or polyethylene, however, has a great tendency to stretch and would do so when driven through a computer printer tractor feed rendering it impossible to feed. This patent also suggests the inclusion of an insert after the envelope is formed but does not disclose how this is done. Insertion of an insert after sealing through a narrow slot could be slow if not impossible.
In U.S. Pat. No. 3,477,194, which discloses a heat sealed thermoplastic package, an infra-red heat source is used to seal the packages. The heat is not applied selectively and is only concentrated in desired sealing regions by the use of a darker border printed on the package which is more receptive to the infrared radiation. Using the method of this patent to produce forms would heat all parts of the form to a temperature which would burst an encapsulated carbonless transfer medium and, therefore, ruin the form. If carbon paper were used, the carbon would melt and run or bleed and cause the pages or sheets to stick. Likewise, the method of sealing disclosed in this patent could not be used in conjunction with my invention for single and multi-ply non-impact printing disclosed in my U.S. patent application Ser. No. 19,150, which uses coatings which change color when heated to a threshhold temperature. Furthermore, the heating method of this patent is comparatively slow and would not be capable of keeping up with current collating equipment which normally produces forms at approximately 200 to 750 forms per minute.
An article for postal use, allowing for a reply, is disclosed in U.S. Pat. No. 3,899,127. The two-way mailer of the patent utilizes a transparent face on the envelope, the removal of the insert exposes a secondary address and the original indicia becomes the return address. Such an arrangement would not meet current U.S. Postal Regulations that require a standard position (upper left) for the return address.
Some typical prior art constructions will now be described. In U.S. Pat. No. 3,104,799, for an envelope assembly, the insert has an extension in the nature of a detachable strip which is sealed to the marginal or detachable strip of the envelope and simultaneously removed when the combined strip is detached. However, because the insert strip has to be glued to the envelope strips, this increases the thickness of the glued region, requires additional glue and all this promotes the above-described tenting.
A sealed envelope assembly with interior mailing material is described in U.S. Pat. No. 3,339,827, where an attempt has been made to decrease the thickness of the glued marginal area. The successive inserts are originally attached to a continuous common marginal strip which is aligned or superimposed with the detachable strips of the envelope. However, prior to gluing the marginal strips of the envelope, the front and back strips of the envelope are turned upwardly and backwardly to expose the marginal material of the insert and the same is trimmed after which the detachable strips of the envelope are glued together. This renders the insert relatively free within the envelope compartment and, in order to avoid excessive shifting, the patentee proposes to use frangible connecting means or fugitive glue. However, when fugitive glue is applied between the top sheet of the insert and the front sheet of the envelope, it tends to stick to the facing surfaces and remove printing and carbon transferred data, thereby decreasing the quality and appearance of the mailed materials.
In U.S. Pat. No. 3,608,816, for a sealed envelope with removable insert, the insert extends beyond the tear strip on one side of the envelope and fugitive adhesive is applied so that pulling on the insert releases it. While the patentee states that this simplifies removal of the insert, it does not overcome the more important problems discussed above.
As suggested above, excessive shifting of an insert inside an envelope may create a problem since the insert may not be properly aligned for imaging information in the proper spaces provided therefor. While it is not normally essential that the insert be absolutely fixed in place, movement should be minimal. An attempt to mobilize an insert within the compartment of a sealed envelope is disclosed in U.S. Pat. No. 3,777,971. To achieve this, the back sheet of the envelope is provided with embossments which abut against the preipheral edges of the insert and thereby immobilize the insert. To the extent that the insert does not extend into the region of the glue lines and is not glued to the front and back sheets of the envelope, the thickness of the marginal edges of the web are decreased and less glue is used, and the tenting problem is somewhat alleviated. However, tenting is not totally eliminated. Also, since the embossments are merely in the nature of crimps in the back sheet of the envelope. These do not provide positive means for positioning the insert.
Another attempt to alleviate the problem of tenting is described in U.S. Pat. No. 3,941,308 for a continuous mailing envelope assembly with inserts and method therefor. As with the previous described patents, to the extent that the insert is not glued to the envelope in the region of the lateral tear strip, and the thickness and the amount of glue used in the region is reduced, tenting may be alleviated to a certain extent. However, tenting will still exist since the disclosed assembly still uses cold, water-soluble glue which does not dry until after the series of envelopes are folded upon each other, thereby permitting relative slippage between the glued layers prior to glue hardening. The mailer envelope disclosed in the patent under discussion has the additional disadvantage in that it teaches the use of glue lines along the transverse perforation or separation lines between adjacent envelopes. Application of adhesive in this manner would result in the glue bleeding through the perforations thereby attaching adjacent envelopes to each other and rendering the entire stack of envelope useless.
Another problem which has existed in the direct mail advertising business is in the use of direct mail letters with reply cards. These letters typically include a patch in the back of the letter sealed along only three sides to form a compartment which is open at the fourth side. A reply postcard or envelope is normally enclosed inside the compartment with the address of the recipient being visible through a die cut opening in the face of the letter. At present, the patch on the back of the letter is glued by means of a cold, water-soluble glue to the back of the letter to form the card or inset receiving compartment. However, after the compartments were formed, another, usually manual, step was required to insert the card, envelope or the like into the compartment.